<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>菜鸟教程(runoob.com)</title>
</head>
<body>
	
	<p id="demo"></p>
	<script>
		var result = Number.MAX_VALUE + Number.MAX_VALUE
		alert(isFinite(result))
		// console.log(Number.MIN_VALUE, Number.MAX_VALUE);

		// var message;
		// alert(message == undefined);
		// alert(age);

		// var type_test = typeof(2);
		// console.log(type_test);
		// console.log(111222);
	</script>
	
</body>
</html>